Lubricant



Patented Jan. 7, 1947 UNITE STATES.

LUBRICANT tion of Maine No Drawing. Application April 24, 1943, Serial No. 484,464

4 Claims. 1

This invention relates to an improved turbine oil. It relates more particularly to a lubricating oil composition consisting principally of a petroleum lubricating oil, the characteristics of the oil being modified by the addition thereto of a relatively small proportion of certain phenol-morpholine-formaldehyde condensation products.

A lubricating oil composition to be used as a turbine oil, and especially in modern marine steam turbines, is subject to very exacting requirements. 'Not only must it perform theordinary function of lubricating the turbine over prolonged periods without interruption but usually it must serve as a coolant, to lubricate the gearing mechanism and to operate oil-actuated governors or control mechanisms having very nice tolerances and lubricate other auxiliary equipment.

Many lubricating oil compositions highly satisfactory for the lubrication of other mechanisms have been found wholly unsuitable for use as a turbine oil. This is probably due primarily to the fact that in normal use turbine oils rapidly become contaminated withwater. Whatever the cause, it is generally recognized that the performance of a turbine oil is not predictable from conventional tests applicable to other oil lubricants.

Essential characteristics of a satisfactory turbine oil include, in addition to ordinary lubricating requirements, extraordinary resistance to oxidation and emulsion in the presence of water. of equal importance is the avoidance of rusting of the metal parts within the oil system of the turbine and auxiliary apparatus under operat-,

ing conditions,

The use of many lubricating oil compositions, otherwise satisfactory as turbine oils, has resulted in the rusting of metal parts within the oil system with consequent serious interference with the operation of the turbine, including oil-actuated governors and other parts, depending upon close tolerances. The results of such rusting not only interfere with the operation of and tend to clog the delicate clearances of the oil system but the products of the rusting appear to catalyze oxidation of the oil with resultant sludge formation which may further aggravate such conditions. The products of such rusting also appear to act as emulsifying agents.

We have found that'the previously experienced rusting of metal parts within the oil system of steam. turbines and the oxidation of the turbine oil itself may be substantially inhibitedby in- 2 pounding the improved turbine oil of invention was produced as follows: In a 1-liter 3-necked flask equipped with a thermometer, dropping funnel and motor-driven stirrer, there were placed 94 grams (1 mole) of phenol and 304 grams (3.5 moles) of morpholine. This mixture was cooled to and maintained within the temperature range of 68-77 F. and 268 grams of formalin (3.3 moles of formaldehyde) was added dropwise in the course of an hour with stirring and cooling. This reaction mixture was stirred for an additonal 2 hours at 68-77 F. and was then heated for 1 hour on a steam bath using a reflux condenser to return volatile reagents. Thereafter the resulting yellow solution was freed from waterfand unreacted phenol, morpholine and formaldehyde by distillation at an absolute pressure of 2.0 millimeters of mercury using an oil bath temperature of 230 F. The residue was alight yellow liquid which solidified on cooling to a waxy white solid. Bythis operation, a yield of 427.5 grams was obtained, which was equivalent to 108% of the theroretical yield of triscorporating in the oil a minor amount of tris- (morpholinomethyl) -phenol or bis- (morpholinomethyl) -phenol.

The tris-(morpholinomethyl) -phenol for com- (morpholinomethyl) -phenol Analysis of the product showed it to contain 10.9% nitrogen as compared with a theoretical nitrogen content of 10.74% for the pure compound.

The excess yield is probably accounted for b the occurrence of side reactions during the operation and to the use of more than the theo retical proportions of two of the reagents as indicated.

By a second operation substantially identical with that previously described, a crude product was obtained which melted at a temperature of about 162-171 F. and contained 10.6% nitrogen. This crude product was purified by two crystallizations from ether andthe purified product was found by analysis to contain 10.4% nitrogen and to melt at a temperature of about 212-214" F.

The bis- (morpholinomethyl) -phenol used in the compounding of our improved turbine oil was produced as follows: In the apparatus previously described there were placed 47 grams (0.5 mole) of phenol and 95.7 grams (1.10 moles) of morpholine. To this mixture, cooled to 68 F., there was added over a period of an hour with stirring, 83 grams of a 40% solution of tri-oxymethylene in water, prepared by refluxing until dissolution was obtained. During this period of one hour, the temperature of the mixture in the flask was maintained between 68 and 77 F. The solution was thereafter allowed to stand for an hour at 80 F. and was then heated for 2 hours on a steam bath with refluxing. The reaction mixture formed two layers. The upper aqueous layer was our present pipetted off and the lower layer was heated at a bath temperature of 220 F. and an absolute pressure of 1.8 millimeters of mercury to remove unreacted materials and any contained moisture. By this procedure a yield of 148 grams of a viscous yellow liquid was obtained which began to solidify on standing. By analysis it was found to contain 9.60% nitrogen as compared with the theoretical nitrogen content of 9.59 for pure bis- (morpholinomethyl) -phenl. The yield obtained by this operation was 102% of the theoretical yield.

The crude bis-(morpholinomethyl) -phenol, prepared as described above, was found to be soluble in oil at normal temperatures in amounts in excess of 0.5%by weight. The tris-(morpholinomethyl) -phenol was found to be soluble in oil at normal temperatures in amounts in excess of by weight. Also, the former was found to be soluble in water to an extent of about 1% and the latter in excess of by weight.

In referring to tris-(morpholinomethyD- phenol and his- (morpholinomethyl) -phenol herein and in the appended claims, we refer, respectivelyfto the above-described products although, of course, we intend to refer by these terms to the same materials by whatever process they may be made. It will be understood that our invention is not predicated upon the identification of the addends as a matter of terminology.

The lubricating il constituent of our improved turbine oil may consist of a petroleum lubricating fraction, such as ordinarily specified for turbine oils. It may with advantage .be a highly refined lubricating oil, for instance an acid-treated petroleum lubricating oil fraction or one which has been subjected to solvent refining, such as a phenol-treated fraction from East Texas crude. The solvent-refined oils have generally been found more resistant to sludging. For example, phenol-treated East Texas neutrals having the following characteristics have been used with advantage:

Sample I Sample II 28. 9 26. 5 405 400 455 455 Viscosity at 100 Ff, S. S. U 192.8 228. l Viscosity at 210 F., S. S. U---" 45.3 46.9 Viscosity index (Dean 6: Davis 87. l 79. 2 Pour. F +10 +5 Neutralization No 0.025 0. 05 Saponificstion No 0. 27 0.27 Carbon residue, (Conrudson) per cent 0. 031 0. 044 Ash, per cent 0. 000 0. 002 Sulfur, per cent. 0. 21 0. 34 Steam emulsion l 42 Demulsibility l, SZH- 600 The steam emulsion numbers appearing in the foregoing tabulation and elsewhere herein were determined in accordance with the method designated Standard Method of Testing for Steam Emulsion of Lubricating Oils, A. S. T. M., Dl57-36.

The demulsibility values appearing in the foregoing tabulation and elsewhere herein were determined in accordance with the method designated Demulsibility Test for Lubricating Oils, prescribed by Federal Standard Stock Catalog, section IV (part 5), Federal Specifications for Lubricants and Liquid Fuels, General Specifications (Methods for Sampling and Testing), VV-L- IQIA, October 2, 193a, Method 320.32.

The unique requirements of a turbine oil have resulted in the formulation of special test methods for determination of the characteristics of phenol.

the oil with respect to rusting and oxidation. The results of rusting tests and oxidation tests, hereinafter noted, were obtained in accordance with methods prescribed by the American Society of Testing Materials and designated, respectively, A. S. T. M. Specification D-665-42T for Turbine Oils and Proposed Method for De termining Oxidation Characteristics of Turbine Oils, section III, Technical Committee 0, A. S. T. M. Committee D-2, July 2, 1941.

We have discovered that substantial protection against rusting of the metal parts within the oil system of steam turbines may be obtained by incorporating in the turbine oil minor proportions of either of the two previously identified compounds. The compound herein designated tris (morpholinomethyl) phenol," either in the crude or recrystallized form, has been found to provide substantially complete protection against rusting, as determined by the previously identified rustin test, when used in proportions even as low as 0.2% by weight. Depending upon the severity of the rusting conditions involved, including temperature, access of air to the oil, amount of water present and the amount of salt or the like in the water, concentrations of tris- (morpholinomethyl) -phenol varying from about 0.05% to about 1% of the oil may be used with advantage.

Though the compound herein designated bis- (morpholinomethyl)-phenol has generally been found to be somewhat less effective in preventing rusting than is the tris-(morpholinomethyl) phenol, similar proportions of the former have been found to inhibit rusting to a material extent. By the incorporation of 0.8% of the bis- (morpholin'omethyl)-phen0l, in the crude form previously identified herein, substantially complete protection against rusting has been obtained.

In addition to substantially inhibiting rusting, we have found these addends to'inhibit oxidation of the oil under conditions encountered by turbine oil, as indicated by the previously identified test for determining oxidation characteristics of turbine oils. In this latter respect the tris- (morpholinoinethyl) -phenol has been found to be superior to the bis-(morpholinomethyl)- However, each has been found to provide substantial protection against oxidation of the turbine oil and sludge formation over substantial periods of operation when used in the previously noted proportions.

It is of interest to note that, by further reducing the number of morpholinomethyl groups, a product was obtained which under test' conditions was practically inert with respect to the oxidation characteristics of the turbine oil composition in which it was incorporated.

The ability of the addends of the present invention effectively to inhibit rusting and oxidation is unexpected and not readily accounted for. This is particularly evident from the inefl'ectiveness of many similar chemical compounds with respect to rusting and oxidation prevention under conditions encountered by turbine oils. An example of such compounds ineffective in preventing rusting under such conditions is tris-(diamylaminomethyl) -pheno1. As previously noted, morpholinomethyl phenol afiorded no protection against oxidation.

In the compounding of our improved turbine oil, a small amount of one of the above-identified addends or a mixture thereof is admixed with a suitable petroleum lubricating oil in the conventional manner of compounding such oil compositions.

In addition to the lubricating oil constituent and the addends previously described, various other addition agents having the ability favorably to influence the characteristics of the turbine oil may be incorporated in the improved turbine oil of our present invention further to improve the properties thereof in various respects. For example, the tris-(morpholinomethyl) -phenol has been found to be compatible with anti-oxidants such as bis-(p-dimethylaminophenyl) -methane, and the latter may with advantage be used in conjunction therewith in our turbine oil as indicated by the following: The phenol-treated East Texas neutral of the preceding sample I had an oxidation induction period of 80 hours. By the addition of 0.1% of bis-(p-dimethylamino- '7 phenyD-methane to this base oil, the oxidation induction period was extended to 560 hours. By the further addition of 0.2% of tris-(morpholinomethyl) -phenol, the oxidation induction period of the oil composition was extended to 710 hours.

As a rust inhibitor, the tris-(morpholinomethyl) -phenol prepared as previously described has been found equally effective in the crude form and as purified by recrystallization. In either form, complete protection against rusting was afforded by proportions as small as 0.2%, as determined by the previously identified turbine oil rusting tests. While from 75% to 100% of the surface of the test specimen, when treated in accordance with the prescribed test method, was rusted by the oil of the preceding sample I, the incorporation of 0.2% of either the crude or recrystallized tris (morpholinomethyl) phenol, prepared as herein described, resulted in a clean specimen. Where only 0.1% of this addend was added, complete protection against rusting was not obtained but rusting was materially inhibited for, though 75% to 100% of the surface of the test specimen was rusted by the base oil alone, only a small portion of the surface of the test specimen showed any indication of rust where I 0.1 of this addend was incorporated in the base oil, Similar results were obtained by incorporating in the base oil 0.2% of the recrystallized tris- (morpholinomethyl) -phenol and 0.1% of the bis- (p-dimethylaminophenol) -methane.

By this prescribed rusting test, the East Texas phenol-treated neutral of sample II resulted in an amount of rusting of the test specimen apprommating that resulting from the use of sample 1. However, by the incorporation of 0.8% of bis- (morpholinomethyl) -phenol in this oil sample. a clean test specimen was obtained. While the incorporation of 0.5% of the bis-(morpholinomethyl) -phenol in the oil of sample II did not aiford complete protection against rusting, the tendency to rust was substantially reduced, the amount of rusting oi the test specimen being of the order of that of sample 1, containing 0.1% of the tris-(morpholinomethyl) phenol. Where less than about 0.5% of bis-(morpholinomethyl) phenol was used, the rusting tendencies of the composition were somewhat greater. However, proportions as low as 0.2% have been found substantially to reduce rusting and even thelower proportions noted herein may frequently be used with advantage. I

The characteristics of our improved lubricating oil composition with respect to oxidation and emulsion are illustrated by the following data obtained by the herein-identified tests. For comparison, the characteristics of the oil constituents lation the oil constituent was that previously identified as sample I.

Emulsion Con- Oxidation characteristics Addend centrainduction WM s. E. 'Demulsi- No. bility i Percent Hours None 80 1 ,1,620+ Tris (morpholinometbyl) phenol, recrystallized. 0. 1 57 l, 560 D0 0.2 410 88 900 Do 0.2 Bis (p dimethylamino 710 75 1,500

phenyl)-methane 0. 1 Tris (morpholinomethyl) phenol, crude 0. l 190 69 1,440 D 0.2 255 65 1,500 Do 0.3 365 75 060 Bis (morpholinomethyl) phenol, crude 0. 5 210 86 380 this base oil of 0.5% and 0.8%, respectively, of

tris-(morpholinomethyl) -phenol, the oxidation induction period was lengthened to 490 hours and 975 hours. Also, by the incorporation of 0.8% of bis- (morpholinomethyD-phenol in sample 11 base oil, the oxidation induction period was extended to 480 hours.

As appears from the foregoing data, our improved turbine oil not only affords complete protection against rusting of the turbine parts but also provides substantial protection against the oxidizing of the oil itself, thus combining characteristics of major importance in turbine operation. A further notable characteristic of our improved turbine oil is its ability to withstand contamination by water without material separation of the addend from the oil or substantial deterioration of the addend.

As previously indicated, depending upon conditions of use, the addends may with advantage be used in proportions ranging from about 0.05%, to 1% on the weight of the oil. Proportions even in excess of 1% may be used, but such larger proportions have not been found necessary. Though proportions less than 0.05% may be used, such smaller proportions are usually not sufficiently mended.

We claim:

1. An improved turbine oil which comprises a petroleum lubricating oil containing a minor proportion, eiiective to retard rusting of metal parts, of a compound of the class consisting of tris- (morpholinomethyl) -phenol and bis-(morpholinomethyl) -phenol.

2. An improved turbine oil which comprises a petroleum lubricating oil containing about 0.05%- 1 of a compound of the class consisting of tris- (morpholinomethyD-phenol and bis-(morpholinomethylJ-phenol.

3. An improved turbine oil which comprises a petroleum lubricating oil containing about 02%- 1% of tris-(morpholinomethyl) -phenol.

4. An improved turbine oil which comprises a petroleum lubricating 011 containing about 0.2% 1% of bis-(morpholinomethyl) -phenol.

ROBERT D. HERLOCKER. MILTON PAUL KLEINHOLZ. i 11.1f- M. WATKINS. 

